Antibiotics and Snake Bites
June, 1996
Dear Dr. Silverio,
Since we can no longer purchase Combiotic, I would like to know
what you recommend in place of it. I have had two suggested:
Liquamycin La-zoo and Penicillin G Procaine. The main things 1
use this for is Kennel Cough and infection after snake bite.
Thank you, Charles Weathers Meridian, MS
Combiotic was the name of an injectable medication which
contained a combination of two antibiotics, Penicillin and
digydrostreptomycin, to achieve a broad spectrum of antibacterial
activity. FDA requirements for re-licensing existing combination
medicines had become more stringent, demanding that drug
companies finance new studies to prove effectiveness of all
combination drugs or take the produce off the market. Combiotic
has been unavailable for a number of years.
Antibiotic treatment is never a guaranteed cure for any
infection, but certain disease syndromes, such as Kennel Cough,
are frequently associated with the same or similar bacterial
infections each time they occur. When a dog has Kennel Cough, or
Infectious Tracheobromchitis, his airways are usually infected
with one of several viruses (Parainfluenza Virus and Canine
Adenoviruses are the most common). There is always secondary
bacterial infection, also (Bordetella is the most common one). A
third organism, Mycoplasma, is also frequently present. The
ingredient in Liquamycin, oxytetracyxline, isa very good choice
for treating infection with either Bordetella or Mycoplasma or
both.
In regard to snake bites in dogs, the problems that need to be
considered are bacterial infection from the bite itself and,
for those species that produce venom, we must treat the poisoning
(or envenomization), which can be life-threatening.
Many types of bacteria are known to live in the mouth of healthy
snakes and can lead to infection of the bite wound inflicted on a
person or a dog. Many of these are anaerobes, bacteria that live
in environments with little or no oxygen, and tend to cause
stubborn and persistent infections. Penicillin is a good
antibiotic to use against anaerobic infections, but has a narrow
spectrum of activity against the more common aerobic bacterial
infections, and is probably not the best choice of antibiotic to
treat bite wounds. Broad spectrum antibiotics, such as
enrofloxacin, may be more appropriate and can be used in
combination with penicillin.
The effects of envenomization may require more than antibiotics
and are best treated at a veterinary hospital. The signs can
range from discomfort and swelling at the site of the bite wound
to severe, life-threatening, systemic signs. The severity depends
on many factors. The size of the victim, the site of the bite and
the time elapsed before appropriate treatment is begun, are all
important. Too much physical activity after the bite occurs can
also increase the uptake of venom. The time of year as well as
the age and aggressiveness of the snake are also factors. The
most important factor may be the species of the snake, however,
geographic location needs to be considered. For example, Mojave
rattlesnake envenomization in some areas, such as Southern
California, can cause rapid death from respiratory paralysis or
severe muscle damage and kidney failure. In other areas, Mojave
rattlesnake bite may be more benign, causing only low blood
pressure and drooping eyelids.
In general, the toxic ingredients in venom can cause disease
through heart dysfunction, blood clotting disorders, neuralgic
disease or severe muscle necrosis. The muscle damage leads to a
buildup of the protein, myoglobin which can, in turn, lead to
kidney failure.
The bites of Copperheads usually cause minimal signs. Western
Diamondbacks are the most likely to cause bleeding problems and
the resultant anemia. Pit vipers cause mostly localized signs
(pain and swelling). Elapids, such as Coral Snakes, frequently
cause salivation, vomiting, apprehension and then convulsions and
respiratory paralysis.
The necessary treatment, then, depends on the signs. At the
veterinarian’s office, samples of blood and urine may be
collected and the bite wound may be cultured and treated.
Possible treatments include intravenous fluids and broad spectrum
antibiotics. Cortisone administration is controversial but is
usually attempted. Antivenin administration is an important part
of therapy but has the potential to cause severe allergic
reactions.
The best advice I can give regarding snake bites is to know what
venomous species of snakes exist in the area where your dogs will
be hunting. If a bite occurs and you are unable to identify the
species involved, whenever there is a chance of envenomization,
you should seek veterinary attention as soon as possible.